A. Field of the Invention
The present invention relates to abutting two pieces of material and then joining them together. More specifically, the present invention relates to devices which may be employed to efficiently create an effective butt joint between two pieces of material.
B. Description of the Prior Art
Butt joints are commonly used in construction of all types. The two members to be joined together are simply cut to length at the desired angle, butted against each other and fastened together using any of various suitable means such as adhesives, screws, nails or a nut in combination with a bolt.
When adhesives are employed, the butt joint is often reinforced with a biscuit or dowels. Holes are drilled into the two members. One end of the biscuit or dowel is inserted into the hole drilled into the first member and the other end of the biscuit or dowel is inserted into the hole drilled into the second member.
Various “knock-down” fasteners have been developed which enable a butt joint between two objects to be assembled and disassembled repeatedly. Such fasteners are often used to assemble inexpensive prefabricated furniture such as bookcases, TV stands, or the like. These fasteners usually consist of a cam dowel screwed into one of the two members to be joined and a cam lock coupled to the other of the two members to be joined. The two members to be joined are brought together so the cam dowel engages the cam lock. A tool is then used to turn the cam lock to secure the two members together. Use of these fasteners typically requires special tools and jigs. As a result, their use is typically limited to mass-produced, as opposed to custom, items. Further, such items are typically stationary in nature and not subjected to repetitive stresses and forces like a railing system. Efforts to employ these fasteners in the construction of railing systems have been unsatisfactory.
A variety of butt joints are found in railing systems. The main components of railing systems are shown in FIGS. 1 and 2. FIG. 1 shows a railing system typically used on a flat, level surface such as a floor or deck. FIG. 2 represents a railing system used on a sloped structure such as a stairway or ramp. Both railing systems have features in common.
The sections of railing 1 shown in FIGS. 1 and 2 each include a pair of newel posts 2 and 4, a top rail 6 comprising sections 8 and 10, a bottom rail 12 comprising sections 14 and 15 and a plurality of balusters 16. These components may be collectively referred to as balustrade. Butt joints are used to join sections 8 and 10 of top rail 6 together and to join the ends of top rail 6 to the newel posts 2 and 4. Likewise, butt joints are used to join sections 14 and 15 of bottom rail 12 together and to join the ends of bottom rail 12 to the newel posts 2 and 4. Butt joints are used to join the bottom of each baluster 16 to the bottom rail 12 and the top of each baluster 16 to the top rail 6. Butt joints are also used to couple the newel posts 2 and 4 to the floor (not shown). Thus, in FIG. 1 alone, there are twenty-two separate butt joints.
Creating a stable and aesthetically pleasing railing system tends to be a very laborious task requiring considerable craftsmanship and skill. Great care must be taken to ensure all the parts shown in FIGS. 1 and 2 are properly aligned and suitably fastened together. In the past, adhesives in combination with biscuits and/or dowels have been employed so that the attachment mechanism is hidden from view. More commonly, and as illustrated in FIG. 3, (also known as hanger bolts) have been employed to make connections when constructing a railing system.
Using dowels and biscuits require great care. If the holes in the two members into which the dowels and biscuits are inserted are not drilled at the correct location, problems with alignment will occur. Also, adhesives require time to dry and, after years of use, will eventually fail. One reason for such failure is expansion and contraction of the wood due to changes in the humidity of the air. Another is the repeated stresses applied to railing systems during use. When screws or nuts and bolts are used, care must be taken, not only to ensure proper alignment, but also to hide the hardware from view. Also, the hardware must typically be recessed with respect to the surfaces of the members to be joined for aesthetic reasons and so the hands of people using the railing are not scratched by the hardware.
While dowels and glue are acceptably employed to mount the balusters of a railing, a stronger and longer lasting mechanism is required for joining two sections of a rail together and to join the ends of a rail to the newel posts. The same is true for joining the bottom of a newel post to the floor. Thus, there is a real need for a mechanism for making a secure and stable butt joint and that allows for periods of adjustment over time to address shrinkage or expansion of the material from which the rails and newel posts are made.
Those skilled in the art recognize that considerable forces are repeatedly encountered by the newel posts and rails over time which can cause these joints to fail unless strong enough hardware is employed. In the prior art, and as illustrated in FIG. 3, relatively large hanger bolts 17 have been employed to attach an end of a rail 6 to a newel post 4. Hanger bolts have two threaded sections, one adapted to screw into the post and the other adapted to receive a nut such as 19. To attach the first end of bolt 17 to the newel post 4, a pilot hole is typically drilled into the newel post 4 and the first end of bolt 17 is screwed into the post 4. Since the bolt 17 has no head, the bolt 17 is typically turned into the newel post 4 using pliers, vice grips or other wrench to grip the second end of the bolt. Care must be taken no ensure the bolt 17 is gripped with an adequate pinching force to allow the first end of bolt 17 to be screwed into the post 4. At the same time, if the tool is applied too tightly, damage will occur to the threads of the second end of the bolt 17 making attachment of the nut 19 difficult or impossible.
This is not the only problem associated with the prior art attachment mechanism shown in FIG. 3. This attachment mechanism requires a relatively large access hole be drilled in from the bottom of the rail 6 and a second through hole is drilled inwardly from the end of the rail until it intersects the access hole. The second end of the hanger bolt is then inserted into the through hole from the end of the rail and advanced until the second end of the hanger bolt resides in the access hole. A washer 18 is then placed over the second end of the hanger bolt via the access hole. This is not an easy task given the size of the access hole relative to the size of the washer and fingers of the installer. After the washer is in place a tightening nut must be started on the threads of the second end of the bolt 17. Again, this is a difficult task because the longitudinal axis of the bolt is perpendicular to the longitudinal axis of the access hole and because the space within the access hole is very limited. It has been reported that in some instances it takes as much as a half hour to install the washer 18 and start the nut 19 onto the hanger bolt 17.
Of course, the connection between the newel post 4 and rail 6 will not be secure unless and until the nut 19 is turned tight. A wrench is typically employed to do so. The wrench extends into the access hole and is, of course, held generally perpendicular to the longitudinal axis of bolt 17. Rotation of the wrench to turn the nut 19 relative to the bolt 17 is limited by the thickness of the shaft of the wrench and the size of the axis hole making tightening the bolt a difficult and awkward task. Further, the position of the balusters and newel posts relative to the wrench can also interfere with tightening of the nut. Even more significant are the challenges faced when the bottom of the rail 6 is at an angle less than 90 degrees relative to the newel post. See, for example, the angle between the bottoms of rails 6 and 12 relative to the newel post 4 in FIG. 2. The smaller this angle, the more the newel post 4 interferes with the use of the wrench to tighten nut 19 onto the bolt 17.
The technique described above has been employed to attach sections of rail together and the bottom of a newel post to a floor, but with similar difficulty. Thus, there is also a real need for hardware that is easier to install and has suitable strength.
In view of the foregoing and in summary, there is a real need for a simple and easy-to-install mechanism for creating a secure, durable, and repeatedly adjustable butt joint between two members